The Question:

Where did the dollar sign originate?

The Answer:

Based on the study of old manuscripts, it appears to have
originated with an abbreviation for "pesos." In revolutionary
times—before the United States was independent, let alone printing its
own currency—the Spanish dollar was widely used in the colonies.
Spanish dollars were also called also known as pesos de 8
reales, or pieces of eight, and "pesos" was abbreviated
"ps." Over time, the "p" and "s" overlapped and merged, forming what
we now know as the dollar sign, $.